Method of making brake linings and the like



Patented Apr. 24, 1923.

I v 52555 "r orrica.

OF CAMBRIDGE, MASSACHUSETTS,

TOMAX BROWN, OF BOSTON, MASSACHUSETTS.

METHOD OF MAKING BRAKE LININGS AND THE LIKE.

No Drawing.

To all wh-o'nm't may concern:

Be it known that I, FREDERICK J. GLEA- son, a citizen of the United States, and resident of Cambridge, county of Middlesex, Commonwealth of Massachusetts, have inventedan Improvement in Method of Haking Brake Linings and the like, of which the following description is a specification.

This invention relates to the manufacture of friction brake linings such as employed for lining the brakes of automobiles and other .uses. It has hitherto been customary to employ for this purpose woven asbestos fiber on account of its heat resisting, noncarboni'zing properties, but the use of th s substance is objectionable not only on account of its relatively high cost, but because a very much of its inherent lack of strength which requires that it be reinforced with a metallic wire mesh and even then the asbestos has a tendency to disintegrate. It has hitherto been considered impracticable to use cotton fiber for this purpose for the reason that no practical way has been known'for preyenting the carbonization and disintegration of the cotton under action of a relatively low heat, i. e., 212 F. I have discovered that by suitable treatment, woven cotton fiber may be impregnated and prepared so that it is capable of withstanding higher degree of heat without carbonlzation or injury, and when treated in accordance with my improved method. a brake lining of cotto fiber may be produced adapted for all ordinary brake lining uses. An essential feature of my invention consists in treating the cotton brake lining which may have been previously impregnated with. suitable filler and friction substance, in a manner so that ,all the volatile elements are distilled off in an atmosphere of a character to prevent the carbonization of the cotton and at a temperature approximating the maximum that the brake lining will be called upon to withstand in use. I preferably provide this non-carbonizing atmosphere by subjecting the material to live steam at a relatively high pressure and for a substantial interval. In carrying out my invention the cotton may be carded and spun in the usual way and may be woven into a fabric, preferably with interposed reinforcing wires or wirenetting. In making up a three-ply lining of cotton I Application filed February 17, 1921 Serial N0. 4=45,S76.

would preferably employ a two-ply wire reinforce. In uniting the layers of material together, they are combined loosely so that the impregnated substance may be taken up thereby readily and to the fullest extent. After the brake lining is thus made up. it is run through a bath composed substantially of a solution of ten per cent (10%) boiled linseed oil, fifteen per cent (15%) turpentine and seventy-five per cent petroleum naphtha in which is dissolved asphaltum, preferably the asphaltic product known as gilsonite in the proportion of two pounds of gilsonite to the gallon. After the brake lining is impregnated in this solution, itis hun I in a drying chamber, and the more volat le elements of the solution are evaporated at a relatively low temperature, i. e., 212 F. which is the carbonization point of cotton. After this the brake lining is placed in a steam vulcanizer and is subjected to theaction of live steam at a pressure of from to pounds per inch, for from 4 to 5 hours. Since this live steam under the pressure named is at a relatively high temperature, i. e. about 500 F. it results that all the substances of the lining that would be volatile at this temperature will be distilled off and the lining will be impregnated with a baking japan filling throughout. The lining is now ready for use except for drying out of the moisture which may be accomplished in an ordinary open-heat oven. T he gilsonite asphaltum substance to which I have made reference is a natural product from certain mines in the Uintah Mountains iirtlie State of Utah, which has been affected by nature to such an extent as to remove the more volatile oils. This substance in its natural form has a co-efiicient of friction well adapted to brake linings.

I do not claim to be the first to use this product in connection with a brake llning, I

but I believe that I am the first to use this product in baking japan and wherein the volatile solvent is removed in the presence of live steam to prevent the carbonization of the cotton or other vegetable fiber of the fabric. While I refer herein to cotton as the material of the fabric, this is to be understood in a broader sense as illustrative ASSIGNOR or ONE-HALF of any suitable vegetable or other, fiber subject to disintegration at higher temperatures. Also while I have found the formula as stated for the baking japan to be a suitable and practicable one, I do not desire to be limited precisely thereto since other, generally equivalent ingredients may be substituted to some extent, as will be understood by those skilled in the art, and to produce a baking japan adapted for the treatment. described. In these as well as other particulars therefore, the present description is to be understood as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description, to indicate the scope of the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: Y

1. The herein described method which consists in impregnating a cotton fabric with a baking japan solution, and subjecting the impregnated fabric to live steam under substantial pressure for a substantial interval.

2.- The herein described method which consists in impregnatinga fabric of vegetable fiber with a baking apan solution and fi subjecting the impregnated fabric to the action of live steam under pressure at a temperature substantially in excess of 212 F. for a substantial interval.

3. The herein described method which consists in impregnating a fabric of vegetable fiber with a baking japan solution, drying the fabric at a relatively low temperature, and then subjecting the fabric to 5. The herein described method which F consists in impregnating a cottom fabric with a baking japan solution and subjecting the impregnated fabric to live steam at apressure of 80 pounds or more for 4 hours or more.

6. The herein described method which consists in impregnating a multi-ply cotton fabric with a baking japan composed of approximately ten per cent boiled linseed oil, fifteen percent turpentine, and seventyve per cent petroleum naphtha in which is dissolved gilsonite asph-altum of a weight of about two pounds to the gallon, and subjecting the impregnated fabric to the action of live steam under substantial pressure at a temperature materially in excess of-212 F. for a substantial period.

In testimony whereof, I have signed my name to this specification.

FREDERICK J. GLEASON. 

